refactor!: modernize registry interface

[shizhMSFT]

What this PR does / why we need it

Refine the interface of registry to match modern dotnet / C# features.

Which issue(s) this PR resolves / fixes

Resolve partially #91

Please check the following list

• Does the affected code have corresponding tests, e.g. unit test, E2E test?
• Does this change require a documentation update?
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have an appropriate license header?

[codecov]

Codecov Report

Attention: 105 lines in your changes are missing coverage. Please review.

Comparison is base (0b2672f) 71.81% compared to head (491693f) 72.35%.

Files	Patch %	Lines
src/OrasProject.Oras/Registry/Remote/Repository.cs	79.59%	32 Missing and 8 partials ⚠️
.../OrasProject.Oras/Registry/Remote/ManifestStore.cs	78.39%	25 Missing and 10 partials ⚠️
src/OrasProject.Oras/Registry/Remote/BlobStore.cs	70.70%	19 Missing and 10 partials ⚠️
src/OrasProject.Oras/Registry/Remote/Registry.cs	94.44%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #92      +/-   ##
==========================================
+ Coverage   71.81%   72.35%   +0.54%     
==========================================
  Files          33       35       +2     
  Lines        1004     1013       +9     
  Branches       88       93       +5     
==========================================
+ Hits          721      733      +12     
+ Misses        232      229       -3     
  Partials       51       51              

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[Wwwsylvia]

LGTM